From 56c00df71036a3560a5f710f527fe7ece54eb665 Mon Sep 17 00:00:00 2001
From: Adam Joseph <adam@westernsemico.com>
Date: Tue, 22 Nov 2022 19:42:06 -0800
Subject: [PATCH] feat(tvix/eval): use backtrace-on-stack-overflow crate

The backtrace-on-stack-overflow create provides best-effort stack
traces when a stack overflow happens.  Since it's running on the
(usually tiny) signal alternate stack this isn't easy.

This is guarded by a new `backtrace_overflow` feature flag and never
enabled (even if that feature is selected) for release builds.  This
is strictly for debugging; there's crazy unsafe voodoo in there.

   https://lib.rs/crates/backtrace-on-stack-overflow

Example output:

```
Stack Overflow:
   0: backtrace_on_stack_overflow::handle_sigsegv
             at /home/amjoseph/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-on-stack-overflow-0.2.0/src/lib.rs:93:40
   1: <unknown>
   2: __rust_probestack
   3: tvix_eval::vm::VM::run_op
             at src/vm.rs:399
   4: tvix_eval::vm::VM::run
             at src/vm.rs:388:23
   5: tvix_eval::vm::VM::enter_frame
             at src/vm.rs:360:22
   6: tvix_eval::value::thunk::Thunk::force
             at src/value/thunk.rs:116:25
   7: tvix_eval::vm::VM::run_op
             at src/vm.rs:801:37
   8: tvix_eval::vm::VM::run
             at src/vm.rs:388:23
   9: tvix_eval::vm::VM::enter_frame
             at src/vm.rs:360:22
  10: tvix_eval::value::thunk::Thunk::force
             at src/value/thunk.rs:116:25
...
```

Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: I1d8a2017f836be7bf91a2223e7adacb86fa1dbb2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7354
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
---
 tvix/eval/Cargo.lock | 345 ++++++++++++++++++++++++++++---------------
 tvix/eval/Cargo.toml |   6 +-
 tvix/eval/src/vm.rs  |   9 ++
 3 files changed, 241 insertions(+), 119 deletions(-)

diff --git a/tvix/eval/Cargo.lock b/tvix/eval/Cargo.lock
index ecc25045b..ff2908281 100644
--- a/tvix/eval/Cargo.lock
+++ b/tvix/eval/Cargo.lock
@@ -3,10 +3,25 @@
 version = 3
 
 [[package]]
-name = "aho-corasick"
-version = "0.7.19"
+name = "addr2line"
+version = "0.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b4f55bd91a0978cbfd91c457a164bab8b4001c833b7f323132c0a4e1922dd44e"
+checksum = "b9ecd88a8c8378ca913a680cd98f0f13ac67383d35993f86c90a70e3f137816b"
+dependencies = [
+ "gimli",
+]
+
+[[package]]
+name = "adler"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
+
+[[package]]
+name = "aho-corasick"
+version = "0.7.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc936419f96fa211c1b9166887b38e5e40b19958e5b895be7c1f93adec7071ac"
 dependencies = [
  "memchr",
 ]
@@ -28,6 +43,32 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
 
+[[package]]
+name = "backtrace"
+version = "0.3.66"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cab84319d616cfb654d03394f38ab7e6f0919e181b1b57e1fd15e7fb4077d9a7"
+dependencies = [
+ "addr2line",
+ "cc",
+ "cfg-if",
+ "libc",
+ "miniz_oxide",
+ "object",
+ "rustc-demangle",
+]
+
+[[package]]
+name = "backtrace-on-stack-overflow"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d51cef6be4d7cb70701727ca9662b5b428833918c13c4095220763ba385ac9bd"
+dependencies = [
+ "backtrace",
+ "libc",
+ "nix 0.23.1",
+]
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -48,9 +89,9 @@ dependencies = [
 
 [[package]]
 name = "bumpalo"
-version = "3.11.0"
+version = "3.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c1ad822118d20d2c234f427000d5acc36eabe1e29a348c89b63dd60b13f28e5d"
+checksum = "572f695136211188308f16ad2ca5c851a712c464060ae6974944458eb83880ba"
 
 [[package]]
 name = "byteorder"
@@ -66,9 +107,9 @@ checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"
 
 [[package]]
 name = "cc"
-version = "1.0.73"
+version = "1.0.77"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2fff2a6927b3bb87f9595d67196a70493f627687a71d87a0d692242c33f58c11"
+checksum = "e9f73505338f7d905b19d18738976aae232eb46b8efc15554ffc56deb5d9ebe4"
 
 [[package]]
 name = "cfg-if"
@@ -89,9 +130,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "3.2.22"
+version = "3.2.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "86447ad904c7fb335a790c9d7fe3d0d971dc523b8ccd1561a520de9a85302750"
+checksum = "71655c45cb9845d3270c9d6df84ebe72b4dad3c2ba3f7023ad47c144e4e473a5"
 dependencies = [
  "atty",
  "bitflags",
@@ -101,7 +142,7 @@ dependencies = [
  "once_cell",
  "strsim",
  "termcolor",
- "textwrap 0.15.1",
+ "textwrap 0.16.0",
 ]
 
 [[package]]
@@ -112,9 +153,9 @@ checksum = "ea0c8bce528c4be4da13ea6fead8965e95b6073585a2f05204bd8f4119f82a65"
 dependencies = [
  "heck",
  "proc-macro-error",
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
- "syn 1.0.99",
+ "syn 1.0.103",
 ]
 
 [[package]]
@@ -219,26 +260,24 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-epoch"
-version = "0.9.10"
+version = "0.9.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "045ebe27666471bb549370b4b0b3e51b07f56325befa4284db65fc89c02511b1"
+checksum = "01a9af1f4c2ef74bb8aa1f7e19706bc72d03598c8a570bb5de72243c7a9d9d5a"
 dependencies = [
  "autocfg",
  "cfg-if",
  "crossbeam-utils",
- "memoffset",
- "once_cell",
+ "memoffset 0.7.1",
  "scopeguard",
 ]
 
 [[package]]
 name = "crossbeam-utils"
-version = "0.8.11"
+version = "0.8.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "51887d4adc7b564537b15adcfb307936f8075dfcd5f00dde9a9f1d29383682bc"
+checksum = "4fb766fa798726286dbbb842f174001dab8abc7b627a1dd86e0b7222a95d929f"
 dependencies = [
  "cfg-if",
- "once_cell",
 ]
 
 [[package]]
@@ -265,12 +304,12 @@ dependencies = [
 
 [[package]]
 name = "ctor"
-version = "0.1.23"
+version = "0.1.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cdffe87e1d521a10f9696f833fe502293ea446d7f256c06128293a4119bdf4cb"
+checksum = "6d2301688392eb071b0bf1a37be05c469d3cc4dbbd95df672fe28ab021e6a096"
 dependencies = [
  "quote 1.0.21",
- "syn 1.0.99",
+ "syn 1.0.103",
 ]
 
 [[package]]
@@ -374,9 +413,9 @@ dependencies = [
 
 [[package]]
 name = "fd-lock"
-version = "3.0.6"
+version = "3.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e11dcc7e4d79a8c89b9ab4c6f5c30b1fc4a83c420792da3542fd31179ed5f517"
+checksum = "bb21c69b9fea5e15dbc1049e4b77145dd0ba1c84019c488102de0dc4ea4b0a27"
 dependencies = [
  "cfg-if",
  "rustix",
@@ -391,15 +430,21 @@ checksum = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
 
 [[package]]
 name = "getrandom"
-version = "0.2.7"
+version = "0.2.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4eb1a864a501629691edf6c15a593b7a51eebaa1e8468e9ddc623de7c9b58ec6"
+checksum = "c05aeb6a22b8f62540c194aac980f2115af067bfe15a0734d7277a768d396b31"
 dependencies = [
  "cfg-if",
  "libc",
  "wasi",
 ]
 
+[[package]]
+name = "gimli"
+version = "0.26.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22030e2c5a68ec659fde1e949a745124b48e6fa8b045b7ed5bd1fe4ccc5c4e5d"
+
 [[package]]
 name = "glob"
 version = "0.3.0"
@@ -435,9 +480,9 @@ dependencies = [
 
 [[package]]
 name = "indexmap"
-version = "1.9.1"
+version = "1.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "10a35a97730320ffe8e2d410b5d3b69279b98d2c14bdb8b70ea89ecf7888d41e"
+checksum = "1885e79c1fc4b10f0e172c475f458b7f7b93061064d98c3293e98c5ba0c8b399"
 dependencies = [
  "autocfg",
  "hashbrown",
@@ -454,15 +499,19 @@ dependencies = [
 
 [[package]]
 name = "io-lifetimes"
-version = "0.7.3"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ea37f355c05dde75b84bba2d767906ad522e97cd9e2eef2be7a4ab7fb442c06"
+checksum = "a7d367024b3f3414d8e01f437f704f41a9f64ab36f9067fa73e526ad4c763c87"
+dependencies = [
+ "libc",
+ "windows-sys",
+]
 
 [[package]]
 name = "itertools"
-version = "0.10.4"
+version = "0.10.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d8bf247779e67a9082a4790b45e71ac7cfd1321331a5c856a74a9faebdab78d0"
+checksum = "b0fd2260e829bddf4cb6ea802289de2f86d6a7a690192fbe91b3f46e0f2c8473"
 dependencies = [
  "either",
 ]
@@ -475,9 +524,9 @@ checksum = "b71991ff56294aa922b450139ee08b3bfc70982c6b2c7562771375cf73542dd4"
 
 [[package]]
 name = "itoa"
-version = "1.0.3"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6c8af84674fe1f223a982c933a0ee1086ac4d4052aa0fb8060c12c6ad838e754"
+checksum = "4217ad341ebadf8d8e724e264f13e593e0648f5b3e94b3896a5df283be015ecc"
 
 [[package]]
 name = "js-sys"
@@ -496,15 +545,15 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.132"
+version = "0.2.137"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8371e4e5341c3a96db127eb2465ac681ced4c433e01dd0e938adbef26ba93ba5"
+checksum = "fc7fcc620a3bff7cdd7a365be3376c97191aeaccc2a603e600951e452615bf89"
 
 [[package]]
 name = "linux-raw-sys"
-version = "0.0.46"
+version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d4d2456c373231a208ad294c33dc5bff30051eafd954cd4caae83a712b12854d"
+checksum = "8f9f08d8963a6c613f4b1a78f4f4a4dbfadf8e6545b2d72861731e4858b8b47f"
 
 [[package]]
 name = "log"
@@ -530,6 +579,24 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "memoffset"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5de893c32cde5f383baa4c04c5d6dbdd735cfd4a794b0debdb2bb1b421da5ff4"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "miniz_oxide"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96590ba8f175222643a85693f33d26e9c8a015f599c216509b1a6894af675d34"
+dependencies = [
+ "adler",
+]
+
 [[package]]
 name = "nibble_vec"
 version = "0.1.0"
@@ -539,6 +606,19 @@ dependencies = [
  "smallvec",
 ]
 
+[[package]]
+name = "nix"
+version = "0.23.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f866317acbd3a240710c63f065ffb1e4fd466259045ccb504130b7f668f35c6"
+dependencies = [
+ "bitflags",
+ "cc",
+ "cfg-if",
+ "libc",
+ "memoffset 0.6.5",
+]
+
 [[package]]
 name = "nix"
 version = "0.24.2"
@@ -561,19 +641,28 @@ dependencies = [
 
 [[package]]
 name = "num_cpus"
-version = "1.13.1"
+version = "1.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "19e64526ebdee182341572e50e9ad03965aa510cd94427a4549448f285e957a1"
+checksum = "f6058e64324c71e02bc2b150e4f3bc8286db6c83092132ffa3f6b1eab0f9def5"
 dependencies = [
  "hermit-abi",
  "libc",
 ]
 
 [[package]]
-name = "once_cell"
-version = "1.14.0"
+name = "object"
+version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2f7254b99e31cad77da24b08ebf628882739a608578bb1bcdfc1f9c21260d7c0"
+checksum = "21158b2c33aa6d4561f1c0a6ea283ca92bc54802a93b263e910746d679a7eb53"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "once_cell"
+version = "1.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "86f0b0d4bf799edbc74508c1e8bf170ff5f41238e5f8225603ca7caaae2b7860"
 
 [[package]]
 name = "oorandom"
@@ -583,9 +672,9 @@ checksum = "0ab1bc2a289d34bd04a330323ac98a1b4bc82c9d9fcb1e66b63caa84da26b575"
 
 [[package]]
 name = "os_str_bytes"
-version = "6.3.0"
+version = "6.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ff7415e9ae3fff1225851df9e0d9e4e5479f947619774677a63572e55e80eff"
+checksum = "9b7820b9daea5457c9f21c69448905d723fbd21136ccf521748f23fd49e723ee"
 
 [[package]]
 name = "output_vt100"
@@ -632,9 +721,9 @@ dependencies = [
 
 [[package]]
 name = "ppv-lite86"
-version = "0.2.16"
+version = "0.2.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eb9f9e6e233e5c4a35559a617bf40a4ec447db2e84c20b55a6f83167b7e57872"
+checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"
 
 [[package]]
 name = "pretty_assertions"
@@ -655,9 +744,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
 dependencies = [
  "proc-macro-error-attr",
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
- "syn 1.0.99",
+ "syn 1.0.103",
  "version_check",
 ]
 
@@ -667,7 +756,7 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
 dependencies = [
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
  "version_check",
 ]
@@ -683,9 +772,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.43"
+version = "1.0.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0a2ca2c61bc9f3d74d2886294ab7b9853abd9c1ad903a3ac7815c58989bb7bab"
+checksum = "5ea3d908b0e36316caf9e9e2c4625cdde190a7e6f440d794667ed17a1855e725"
 dependencies = [
  "unicode-ident",
 ]
@@ -729,7 +818,7 @@ version = "1.0.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bbe448f377a7d6961e30f5955f9b8d106c3f5e449d493ee1b125c1d43c2b5179"
 dependencies = [
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
 ]
 
 [[package]]
@@ -811,11 +900,10 @@ dependencies = [
 
 [[package]]
 name = "rayon"
-version = "1.5.3"
+version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bd99e5772ead8baa5215278c9b15bf92087709e9c1b2d1f97cdb5a183c933a7d"
+checksum = "1e060280438193c554f654141c9ea9417886713b7acd75974c85b18a69a88e0b"
 dependencies = [
- "autocfg",
  "crossbeam-deque",
  "either",
  "rayon-core",
@@ -823,9 +911,9 @@ dependencies = [
 
 [[package]]
 name = "rayon-core"
-version = "1.9.3"
+version = "1.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "258bcdb5ac6dad48491bb2992db6b7cf74878b0384908af124823d118c99683f"
+checksum = "cac410af5d00ab6884528b4ab69d1e8e146e8d471201800fa1b4524126de6ad3"
 dependencies = [
  "crossbeam-channel",
  "crossbeam-deque",
@@ -864,9 +952,9 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "1.6.0"
+version = "1.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4c4eb3267174b8c6c2f654116623910a0fef09c4753f8dd83db29c48a0df988b"
+checksum = "e076559ef8e241f2ae3479e36f97bd5741c0330689e217ad51ce2c76808b868a"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -881,9 +969,9 @@ checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.27"
+version = "0.6.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a3f87b73ce11b1619a3c6332f45341e0047173771e8b8b73f87bfeefb7b56244"
+checksum = "456c603be3e8d448b072f410900c09faf164fbce2d480456f50eea6e25f9c848"
 
 [[package]]
 name = "remove_dir_all"
@@ -904,17 +992,23 @@ dependencies = [
 
 [[package]]
 name = "rowan"
-version = "0.15.9"
+version = "0.15.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7aeb3c95eac7794161baf500b5d4647217ffb32b6660c04d3bb087c834cb58f4"
+checksum = "5811547e7ba31e903fe48c8ceab10d40d70a101f3d15523c847cce91aa71f332"
 dependencies = [
  "countme",
  "hashbrown",
- "memoffset",
+ "memoffset 0.6.5",
  "rustc-hash",
  "text-size",
 ]
 
+[[package]]
+name = "rustc-demangle"
+version = "0.1.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7ef03e0a2b150c7a90d01faf6254c9c48a41e95fb2a8c2ac1c6f0d2b9aefc342"
+
 [[package]]
 name = "rustc-hash"
 version = "1.1.0"
@@ -923,9 +1017,9 @@ checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
 
 [[package]]
 name = "rustix"
-version = "0.35.9"
+version = "0.36.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "72c825b8aa8010eb9ee99b75f05e10180b9278d161583034d7574c9d617aeada"
+checksum = "0b1fbb4dfc4eb1d390c02df47760bb19a84bb80b301ecc947ab5406394d8223e"
 dependencies = [
  "bitflags",
  "errno",
@@ -949,7 +1043,7 @@ dependencies = [
  "libc",
  "log",
  "memchr",
- "nix",
+ "nix 0.24.2",
  "radix_trie",
  "scopeguard",
  "unicode-segmentation",
@@ -981,9 +1075,9 @@ checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
 [[package]]
 name = "serde"
-version = "1.0.144"
+version = "1.0.147"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0f747710de3dcd43b88c9168773254e809d8ddbdf9653b84e2554ab219f17860"
+checksum = "d193d69bae983fc11a79df82342761dfbf28a99fc8d203dca4c3c1b590948965"
 
 [[package]]
 name = "serde_cbor"
@@ -997,31 +1091,31 @@ dependencies = [
 
 [[package]]
 name = "serde_derive"
-version = "1.0.144"
+version = "1.0.147"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "94ed3a816fb1d101812f83e789f888322c34e291f894f19590dc310963e87a00"
+checksum = "4f1d362ca8fc9c3e3a7484440752472d68a6caa98f1ab81d99b5dfe517cec852"
 dependencies = [
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
- "syn 1.0.99",
+ "syn 1.0.103",
 ]
 
 [[package]]
 name = "serde_json"
-version = "1.0.86"
+version = "1.0.89"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "41feea4228a6f1cd09ec7a3593a682276702cd67b5273544757dae23c096f074"
+checksum = "020ff22c755c2ed3f8cf162dbb41a7268d934702f3ed3631656ea597e08fc3db"
 dependencies = [
- "itoa 1.0.3",
+ "itoa 1.0.4",
  "ryu",
  "serde",
 ]
 
 [[package]]
 name = "smallvec"
-version = "1.9.0"
+version = "1.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2fd0db749597d91ff862fd1d55ea87f7855a744a8425a64695b6fca237d1dad1"
+checksum = "a507befe795404456341dfab10cef66ead4c041f62b8b11bbb92bffe5d0953e0"
 
 [[package]]
 name = "smol_str"
@@ -1050,10 +1144,10 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1bd9c2155aa89fb2c2cb87d99a610c689e7c47099b3e9f1c8a8f53faf4e3d2e3"
 dependencies = [
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
  "structmeta-derive",
- "syn 1.0.99",
+ "syn 1.0.103",
 ]
 
 [[package]]
@@ -1062,9 +1156,9 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bafede0d0a2f21910f36d47b1558caae3076ed80f6f3ad0fc85a91e6ba7e5938"
 dependencies = [
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
- "syn 1.0.99",
+ "syn 1.0.103",
 ]
 
 [[package]]
@@ -1080,11 +1174,11 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.99"
+version = "1.0.103"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "58dbef6ec655055e20b86b15a8cc6d439cca19b667537ac6a1369572d151ab13"
+checksum = "a864042229133ada95abf3b54fdc62ef5ccabe9515b64717bcb9a1919e59445d"
 dependencies = [
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
  "unicode-ident",
 ]
@@ -1149,10 +1243,10 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "62d6408d1406657be2f9d1701fbae379331d30d2f6e92050710edb0d34eeb480"
 dependencies = [
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
  "structmeta",
- "syn 1.0.99",
+ "syn 1.0.103",
 ]
 
 [[package]]
@@ -1172,28 +1266,28 @@ dependencies = [
 
 [[package]]
 name = "textwrap"
-version = "0.15.1"
+version = "0.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "949517c0cf1bf4ee812e2e07e08ab448e3ae0d23472aee8a06c985f0c8815b16"
+checksum = "222a222a5bfe1bba4a77b45ec488a741b3cb8872e5e499451fd7d0129c9c7c3d"
 
 [[package]]
 name = "thiserror"
-version = "1.0.35"
+version = "1.0.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c53f98874615aea268107765aa1ed8f6116782501d18e53d08b471733bea6c85"
+checksum = "10deb33631e3c9018b9baf9dcbbc4f737320d2b576bac10f6aefa048fa407e3e"
 dependencies = [
  "thiserror-impl",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "1.0.35"
+version = "1.0.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f8b463991b4eab2d801e724172285ec4195c650e8ec79b149e6c2a8e6dd3f783"
+checksum = "982d17546b47146b28f7c22e3d08465f6b8903d0ea13c1660d9d84a6e7adcdbb"
 dependencies = [
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
- "syn 1.0.99",
+ "syn 1.0.103",
 ]
 
 [[package]]
@@ -1210,7 +1304,8 @@ dependencies = [
 name = "tvix-eval"
 version = "0.1.0"
 dependencies = [
- "clap 3.2.22",
+ "backtrace-on-stack-overflow",
+ "clap 3.2.23",
  "codemap",
  "codemap-diagnostic",
  "criterion",
@@ -1237,16 +1332,16 @@ dependencies = [
 name = "tvix-eval-builtin-macros"
 version = "0.0.1"
 dependencies = [
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
- "syn 1.0.99",
+ "syn 1.0.103",
 ]
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.4"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dcc811dc4066ac62f84f11307873c4850cb653bfa9b1719cee2bd2204a4bc5dd"
+checksum = "6ceab39d59e4c9499d4e5a8ee0e2735b891bb7308ac83dfb4e80cad195c9f6f3"
 
 [[package]]
 name = "unicode-segmentation"
@@ -1314,9 +1409,9 @@ dependencies = [
  "bumpalo",
  "log",
  "once_cell",
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
- "syn 1.0.99",
+ "syn 1.0.103",
  "wasm-bindgen-shared",
 ]
 
@@ -1336,9 +1431,9 @@ version = "0.2.83"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "07bc0c051dc5f23e307b13285f9d75df86bfdf816c5721e573dec1f9b8aa193c"
 dependencies = [
- "proc-macro2 1.0.43",
+ "proc-macro2 1.0.47",
  "quote 1.0.21",
- "syn 1.0.99",
+ "syn 1.0.103",
  "wasm-bindgen-backend",
  "wasm-bindgen-shared",
 ]
@@ -1392,46 +1487,60 @@ checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
 [[package]]
 name = "windows-sys"
-version = "0.36.1"
+version = "0.42.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ea04155a16a59f9eab786fe12a4a450e75cdb175f9e0d80da1e17db09f55b8d2"
+checksum = "5a3e1820f08b8513f676f7ab6c1f99ff312fb97b553d30ff4dd86f9f15728aa7"
 dependencies = [
+ "windows_aarch64_gnullvm",
  "windows_aarch64_msvc",
  "windows_i686_gnu",
  "windows_i686_msvc",
  "windows_x86_64_gnu",
+ "windows_x86_64_gnullvm",
  "windows_x86_64_msvc",
 ]
 
 [[package]]
-name = "windows_aarch64_msvc"
-version = "0.36.1"
+name = "windows_aarch64_gnullvm"
+version = "0.42.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9bb8c3fd39ade2d67e9874ac4f3db21f0d710bee00fe7cab16949ec184eeaa47"
+checksum = "41d2aa71f6f0cbe00ae5167d90ef3cfe66527d6f613ca78ac8024c3ccab9a19e"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.42.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd0f252f5a35cac83d6311b2e795981f5ee6e67eb1f9a7f64eb4500fbc4dcdb4"
 
 [[package]]
 name = "windows_i686_gnu"
-version = "0.36.1"
+version = "0.42.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "180e6ccf01daf4c426b846dfc66db1fc518f074baa793aa7d9b9aaeffad6a3b6"
+checksum = "fbeae19f6716841636c28d695375df17562ca208b2b7d0dc47635a50ae6c5de7"
 
 [[package]]
 name = "windows_i686_msvc"
-version = "0.36.1"
+version = "0.42.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2e7917148b2812d1eeafaeb22a97e4813dfa60a3f8f78ebe204bcc88f12f024"
+checksum = "84c12f65daa39dd2babe6e442988fc329d6243fdce47d7d2d155b8d874862246"
 
 [[package]]
 name = "windows_x86_64_gnu"
-version = "0.36.1"
+version = "0.42.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4dcd171b8776c41b97521e5da127a2d86ad280114807d0b2ab1e462bc764d9e1"
+checksum = "bf7b1b21b5362cbc318f686150e5bcea75ecedc74dd157d874d754a2ca44b0ed"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.42.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09d525d2ba30eeb3297665bd434a54297e4170c7f1a44cad4ef58095b4cd2028"
 
 [[package]]
 name = "windows_x86_64_msvc"
-version = "0.36.1"
+version = "0.42.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c811ca4a8c853ef420abd8592ba53ddbbac90410fab6903b3e79972a631f7680"
+checksum = "f40009d85759725a34da6d89a94e63d7bdc50a862acf0dbc7c8e488f1edcb6f5"
 
 [[package]]
 name = "yansi"
diff --git a/tvix/eval/Cargo.toml b/tvix/eval/Cargo.toml
index ce7274588..1d42b793d 100644
--- a/tvix/eval/Cargo.toml
+++ b/tvix/eval/Cargo.toml
@@ -28,6 +28,7 @@ serde = "1.0"
 serde_json = "1.0"
 regex = "1.6.0"
 builtin-macros = { path = "./builtin-macros", package = "tvix-eval-builtin-macros" }
+backtrace-on-stack-overflow = { version = "0.2.0", optional = true }
 
 # rnix has not been released in a while (as of 2022-09-23), we will
 # use it from git.
@@ -43,7 +44,7 @@ itertools = "0.10.3"
 tempdir = "0.3.7"
 
 [features]
-default = [ "repl", "impure", "arbitrary", "nix_tests" ]
+default = [ "repl", "impure", "arbitrary", "nix_tests", "backtrace_overflow" ]
 
 # Enables running the Nix language test suite from the original C++
 # Nix implementation (at version 2.3) against Tvix.
@@ -58,6 +59,9 @@ impure = []
 # Enables Arbitrary impls for internal types (required to run tests)
 arbitrary = [ "proptest", "test-strategy" ]
 
+# For debugging use only; not appropriate for production use.
+backtrace_overflow = [ "backtrace-on-stack-overflow" ]
+
 [[bench]]
 name = "eval"
 harness = false
diff --git a/tvix/eval/src/vm.rs b/tvix/eval/src/vm.rs
index aa03ffd1e..41640a32b 100644
--- a/tvix/eval/src/vm.rs
+++ b/tvix/eval/src/vm.rs
@@ -148,6 +148,15 @@ macro_rules! cmp_op {
 
 impl<'o> VM<'o> {
     pub fn new(nix_search_path: NixSearchPath, observer: &'o mut dyn RuntimeObserver) -> Self {
+        // Backtrace-on-stack-overflow is some seriously weird voodoo and
+        // very unsafe.  This double-guard prevents it from accidentally
+        // being enabled on release builds.
+        #[cfg(debug_assertions)]
+        #[cfg(feature = "backtrace_overflow")]
+        unsafe {
+            backtrace_on_stack_overflow::enable();
+        };
+
         Self {
             nix_search_path,
             observer,